#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
//10
//int main()
//{
//	int arr1[] = { 1, 2, 3, 4, 5 };
//	int arr2[] = { 6, 7, 8, 9, 10 };
//	int sz = sizeof(arr1) / sizeof(arr1[0]);
//	for (int i = 0; i < sz; i++)
//	{
//		int tem = arr1[i];
//		arr1[i] = arr2[i];
//		arr2[i] = tem;
//	}
//	return 0;
//}

//11
int main()
{
	int a = 10;
	int arr[10] = { 0 };
	for (int i = 0; i < a; i++)
	{
		scanf("%d", &arr[i]);
	}
	int sum = 0;
	for (int i = 0; i < a; i++)
	{
		sum += arr[i];
	}
	double avg = sum / 10.0;
	printf("%lf",avg);
	return 0;
}